Method and device for controlling helium inlet pressure through variable-volume buffer tank

Abstract

The invention provides a method and device for controlling helium inlet pressure through a variable-volume buffer tank, and relates to the field of low-temperature systems, and the device comprises a constant-temperature system and a pressure adjusting system; a buffer tank is arranged on the pressure adjusting system, and a first pressure gauge and a pressure release valve are arranged on one side of the buffer tank; the buffer tank is of a variable volume structure; the volume of the buffer tank is adjusted to change the gas pressure in the buffer tank, so that the helium pressure at the inlet of the constant-temperature system is kept stable; a second pressure gauge and a third pressure gauge are arranged between the constant temperature system and the pressure adjusting system, and the constant temperature system and the pressure adjusting system are connected through the second pressure gauge and the third pressure gauge. According to the method and device for controlling the helium inlet pressure through the variable-volume buffer tank, the helium pressure is adjusted by adjusting the volume of the buffer tank, it is ensured that the pressure of helium at the inlet of the thermostat is kept stable, and therefore the problem of pressure fluctuation in the prior art is solved.

Description

Technical Field

[0001] The invention relates to the field of cryogenic systems, and in particular to a method and a device for controlling helium inlet pressure through a variable volume buffer tank. Background Art

[0002] In cryogenic refrigeration technology, superconducting technology and high-energy physics experiments, helium is widely used as an important cooling medium in various cryogenic experiments and equipment. A typical helium circulation system includes passing helium at room temperature and pressure through a pipeline into the heat exchanger of a cryogenic refrigerator for pre-cooling, then entering a secondary heat exchanger to cool and liquefy into liquid helium, and then the liquid helium cools the sample through a pipeline, and finally is pressurized by a circulating pump to restore to room temperature and pressure and enter the system. However, there is an important problem with the current helium circulation system: the pressurized helium may not be able to fully recover to room temperature and pressure, or pressure fluctuations may occur during operation. Especially when the load changes greatly, the pressure in the helium pipeline is prone to fluctuations, which in turn affects the normal operation of the thermostat, causing unstable temperature control and reducing the cooling effect.

[0003] In order to ensure the stability of the helium pressure at the thermostat inlet, the existing technology usually uses gas tanks, bypass pipes, heaters, etc. to adjust the pressure, but these solutions still have certain limitations in terms of adjustment range, response speed and accuracy. Summary of the invention

[0004] The object of the present invention is to provide a method and device for controlling the helium inlet pressure through a variable volume buffer tank, by adjusting the volume of the buffer tank to adjust the helium pressure, to ensure that the helium pressure at the thermostat inlet remains stable, thereby solving the pressure fluctuation problem in the prior art.

[0005] To achieve the above object, the present invention provides a device for controlling the helium inlet pressure through a variable volume buffer tank, comprising a constant temperature system and a pressure regulating system;

[0006] The pressure regulating system is provided with a buffer tank, and one side of the buffer tank is provided with a first pressure gauge and a pressure relief valve;

[0007] The buffer tank is a variable volume structure; the buffer tank adjusts its volume to change the gas pressure in the buffer tank, ensuring that the helium pressure at the inlet of the constant temperature system remains stable;

[0008] A second pressure gauge and a third pressure gauge are provided between the constant temperature system and the pressure regulating system, and the constant temperature system and the pressure regulating system are connected through the second pressure gauge and the third pressure gauge.

[0009] Preferably, the buffer tank is a bellows structure or a piston structure.

[0010] Preferably, the constant temperature system is provided with a vacuum cover, a low-temperature refrigerator is provided outside the vacuum cover, a first bellows is provided between the vacuum cover and the low-temperature refrigerator, and a positive pressure chamber is provided inside the vacuum cover and connected to the vacuum refrigerator and the first bellows;

[0011] A primary cold screen and a secondary cold screen are sequentially arranged at one end of the positive pressure chamber, and a low-temperature throttle valve and a sample stage are arranged in the secondary cold screen.

[0012] Preferably, the second pressure gauge and the third pressure gauge are both connected to the buffer tank;

[0013] A flow meter and a first valve are also provided between the second pressure gauge and the buffer tank;

[0014] A second valve is provided between the third pressure gauge and the buffer tank.

[0015] Preferably, a circulation pump is further provided between the second pressure gauge and the third pressure gauge, and the circulation pump is connected in parallel with the buffer tank.

[0016] Preferably, the positive pressure chamber, the primary cold shield, the secondary cold shield, the low temperature throttle valve and the sample stage are all located in a vacuum cover.

[0017] Preferably, the first pressure gauge, the second pressure gauge and the third pressure gauge obtain pressure values, and adjust the volume of the buffer tank according to the pressure values.

[0018] Preferably, the first bellows is connected to a refrigerator and a vacuum cover respectively.

[0019] Preferably, a cold water bath unit is provided at the outlet end of the buffer tank.

[0020] A method for controlling helium inlet pressure through a variable volume buffer tank, comprising:

[0021] When helium enters the constant temperature system through the pipeline, the pressure in the pipeline is adjusted by the pressure regulating system. If the pressure fluctuates, the constant temperature system adjusts the volume of the buffer tank through the control algorithm and the pressure relief valve:

[0022] When the helium pressure is too high, the volume of the buffer tank will be increased to reduce the pressure inside the pipeline and the buffer tank; when the helium pressure is too low, the volume will be reduced, the pressure inside the buffer tank will increase, and the helium pressure in the pipeline will be supplemented;

[0023] The control algorithm adjusts the volume change of the buffer tank in real time according to the data provided by the first pressure gauge, the second pressure gauge and the third pressure gauge, so as to maintain the pressure of the inlet helium of the constant temperature system stable.

[0024] Therefore, the present invention adopts the above-mentioned method and device for controlling the helium inlet pressure through a variable volume buffer tank, and the technical effects are as follows:

[0025] (1) Accurately adjust the helium pressure: The variable volume buffer tank can accurately adjust the helium pressure to avoid the impact of pressure fluctuations on the thermostat and ensure the stability of the helium pressure at the thermostat inlet.

[0026] (2) Improve response speed and control accuracy: By monitoring the helium pressure in real time and adjusting the buffer tank volume according to the feedback signal, the system can quickly respond to changes in helium pressure and improve the system adjustment accuracy and response speed.

[0027] (3) Simple and efficient structural design: The design of the buffer tank with bellows structure and piston structure is simple and efficient, which can achieve precise pressure regulation without adding too many complex devices, reduce system costs and simplify installation and maintenance.

[0028] (4) Energy saving and high efficiency: By precisely adjusting the pressure, unnecessary energy waste is avoided, the operating efficiency of the helium circulation system is optimized, and the cooling effect is improved.

[0029] (5) Strong adaptability and good integration: The variable volume buffer tank has a compact structure design and can be easily integrated into the existing helium circulation system without large-scale changes to the existing equipment. It has good adaptability and flexibility.

[0030] (6) Enhance system stability and reliability: By maintaining the stability of the helium pressure at the thermostat inlet, the long-term stable operation of the system is ensured to avoid the reduction of cooling effect or equipment damage caused by unstable pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention is a schematic diagram of a device for controlling the helium inlet pressure through a variable volume buffer tank.

[0032] Reference numerals

[0033] 1. Cryogenic refrigerator; 2. First bellows; 3. Positive pressure chamber; 4. Vacuum cover; 5. First-stage cold screen; 6. Cryogenic throttle valve; 7. Sample table; 8. Second-stage cold screen; 9. Third pressure gauge; 10. Buffer tank; 11. First valve; 12. Circulating pump; 13. Flow meter; 14. Second pressure gauge; 15. First pressure gauge; 16. Pressure relief valve; 17. Second valve; 18. Cold water bath unit; 19. Host computer. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0035] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0036] Embodiment 1

[0037] like Figure 1 As shown, a device for controlling the inlet pressure of helium through a variable volume buffer tank includes a constant temperature system, a pressure regulating system, a first valve, a flow meter, a second pressure gauge, a third pressure gauge, a second valve, and a circulation pump. The constant temperature system is a common system on the market, and the pressure regulating system can adjust the gas pressure in the gas supply pipeline at a lower cost and a smaller space volume.

[0038] The constant temperature system includes a low-temperature refrigerator, a first bellows, a positive pressure chamber, a vacuum cover, a first-stage cold shield, a second-stage cold shield, a low-temperature throttle valve, and a sample stage.

[0039] The pressure regulating system includes a buffer tank, a first pressure gauge, and a pressure relief valve.

[0040] Helium flows through the second pressure gauge into the positive pressure chamber, and then is cooled down for the first time under the action of the first-level cold screen. Then, the helium flows through the low-temperature throttle valve to reach the sample stage, and becomes liquid under the action of the second-level cold screen. Under the action of the circulating pump, the liquid helium flows through the third pressure gauge and the second valve into the buffer tank. The helium pressure value obtained by the first pressure gauge, the second pressure gauge and the third pressure gauge is used to adjust the volume of the buffer tank by the host computer to adjust the helium state and the pressure in the gas supply pipeline. When the adjustment limit is exceeded, the pressure relief valve is used to reduce the pressure of the buffer tank and the gas supply pipeline.

[0041] The helium flows out of the buffer tank in gaseous form into the cold water bath unit, where the helium is cooled to room temperature. The helium then flows through the first valve and flow meter and enters the next cycle.

[0042] The first-level cold screen and the second-level cold screen are connected to a low-temperature refrigerator to achieve a cooling effect.

[0043] The cryogenic refrigerator, positive pressure chamber, first-stage cold shield, second-stage cold shield, cryogenic throttle valve, and sample stage are all located in the vacuum cover, which effectively isolates external heat radiation and ensures the stability of helium in a low-temperature environment.

[0044] A circulation pump 12 is further provided between the second pressure gauge 14 and the third pressure gauge 9 , and the circulation pump 12 is connected in parallel with the buffer tank 10 .

[0045] The circulation pump 12 is responsible for extracting liquid helium from the gas supply pipeline and transporting it to the pressure regulating system through the pipeline. The pressure regulating system converts the helium into gaseous state according to the set pressure value and returns it to the gas supply pipeline to complete a cycle.

[0046] The first pressure gauge is used to monitor the pressure inside the buffer tank in real time. It is an important tool for control and monitoring, and can accurately reflect the pressure status inside the buffer tank. By reading the value of the pressure gauge, the operator can understand the current pressure of the system and make corresponding adjustments accordingly.

[0047] The pressure relief valve is a safety protection device in the pressure regulation system. When the pressure of the buffer tank or the entire system exceeds the preset safety value, the pressure relief valve will automatically open to release the excess pressure to prevent the system from being damaged due to overpressure. The set pressure of the pressure relief valve is usually determined according to the maximum working pressure of the gas supply pipeline to ensure timely response when the pressure is abnormal.

[0048] The buffer tank 10 is a bellows structure or a piston structure.

[0049] The buffer tank 10 in the form of a bellows: The buffer tank 10 is designed in the form of a bellows. The outer shell of the bellows can expand or contract under the action of gas pressure, thereby changing the volume and adjusting the pressure in the buffer tank 10.

[0050] Piston type buffer tank 10: The buffer tank 10 is designed as a piston type structure. The buffer tank 10 is equipped with a sliding piston, and the volume is changed by adjusting the position of the piston, thereby adjusting the pressure of the helium in the buffer tank 10. The top of the piston can slide with the cover plate of the buffer tank 10, and the movement of the piston is adjusted by the driving mechanism to adjust the volume change.

[0051] A method for controlling helium inlet pressure through a variable volume buffer tank 10, comprising:

[0052] When helium enters the constant temperature system through the pipeline, the pressure in the pipeline is adjusted by the pressure regulating system. If the pressure fluctuates, the constant temperature system adjusts the volume of the buffer tank 10 through the control algorithm and the pressure relief valve 16:

[0053] When the helium pressure is too high, the volume of the buffer tank 10 will be increased to reduce the pressure inside the pipeline and the buffer tank 10; when the helium pressure is too low, the volume will be reduced, the pressure inside the buffer tank 10 will increase, and the helium pressure in the pipeline will be supplemented;

[0054] The control algorithm adjusts the volume change of the buffer tank 10 in real time according to the data provided by the first pressure gauge 15, the second pressure gauge 14 and the third pressure gauge 9, so as to maintain the pressure of the helium gas at the inlet of the constant temperature system stable.

[0055] Therefore, the present invention adopts the above-mentioned method and device for controlling the helium inlet pressure through a variable volume buffer tank, and adjusts the helium pressure by adjusting the volume of the buffer tank to ensure that the helium pressure at the thermostat inlet remains stable, thereby solving the pressure fluctuation problem in the prior art.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A device for controlling the inlet pressure of helium through a variable volume buffer tank, characterized in that: Including constant temperature system and pressure regulation system; The pressure regulating system is provided with a buffer tank, and one side of the buffer tank is provided with a first pressure gauge and a pressure relief valve; The buffer tank is a variable volume structure; the buffer tank adjusts its volume to change the gas pressure in the buffer tank, ensuring that the helium pressure at the inlet of the constant temperature system remains stable; A second pressure gauge and a third pressure gauge are provided between the constant temperature system and the pressure regulating system, and the constant temperature system and the pressure regulating system are connected through the second pressure gauge and the third pressure gauge.

2. The device for controlling the helium inlet pressure by a variable volume buffer tank according to claim 1, characterized in that: The buffer tank is a bellows structure or a piston structure.

3. The device for controlling the helium inlet pressure through a variable volume buffer tank according to claim 1, characterized in that: The constant temperature system is provided with a vacuum cover, a low-temperature refrigerator is provided outside the vacuum cover, a first bellows is provided between the vacuum cover and the low-temperature refrigerator, and a positive pressure chamber is provided inside the vacuum cover and connected to the vacuum refrigerator and the first bellows; A primary cold screen and a secondary cold screen are sequentially arranged at one end of the positive pressure chamber, and a low-temperature throttle valve and a sample stage are arranged in the secondary cold screen.

4. The device for controlling the helium inlet pressure by a variable volume buffer tank according to claim 1, characterized in that: The second pressure gauge and the third pressure gauge are both connected to the buffer tank; A flow meter and a first valve are also provided between the second pressure gauge and the buffer tank; A second valve is provided between the third pressure gauge and the buffer tank.

5. The device for controlling the helium inlet pressure through a variable volume buffer tank according to claim 1, characterized in that: A circulation pump is also provided between the second pressure gauge and the third pressure gauge, and the circulation pump is connected in parallel with the buffer tank.

6. The device for controlling the helium inlet pressure through a variable volume buffer tank according to claim 3, characterized in that: The positive pressure chamber, the first-stage cold shield, the second-stage cold shield, the low-temperature throttle valve and the sample stage are all located in the vacuum cover.

7. The device for controlling the helium inlet pressure through a variable volume buffer tank according to claim 1, characterized in that: The first pressure gauge, the second pressure gauge, and the third pressure gauge obtain pressure values, and adjust the volume of the buffer tank according to the pressure values.

8. The device for controlling the helium inlet pressure through a variable volume buffer tank according to claim 3, characterized in that: The first bellows is connected to a refrigerator and a vacuum cover respectively.

9. The device for controlling the helium inlet pressure through a variable volume buffer tank according to claim 1, characterized in that: A cold water bath unit is provided at the outlet end of the buffer tank.

10. A method for controlling the helium inlet pressure by a variable volume buffer tank, characterized in that: include: When helium enters the constant temperature system through the pipeline, the pressure in the pipeline is adjusted by the pressure regulating system. If the pressure fluctuates, the constant temperature system adjusts the volume of the buffer tank through the control algorithm and the pressure relief valve: When the helium pressure is too high, the volume of the buffer tank will be increased, reducing the pressure inside the pipeline and the buffer tank; when the helium pressure is too low, the volume will be reduced, the pressure inside the buffer tank will increase, and the helium pressure in the pipeline will be supplemented; According to the data provided by the first pressure gauge, the second pressure gauge and the third pressure gauge, the volume change of the buffer tank is adjusted in real time to keep the pressure of the inlet helium of the constant temperature system stable.

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